BackgroundDehorning is a common practice involving calves on dairy operations in the United States. However, less than 20% of producers report using analgesics or anesthetics during dehorning. Administration of a systemic analgesic drug at the time of dehorning may be attractive to dairy producers since cornual nerve blocks require 10 – 15 min to take effect and only provide pain relief for a few hours. The primary objectives of this trial were to 1 describe the compartmental pharmacokinetics of meloxicam in calves after IV administration at 0.5 mg-kg and 2 to determine the effect of meloxicam n = 6 or placebo n = 6 treatment on serum cortisol response, plasma substance P SP concentrations, heart rate HR, activity and weight gain in calves after scoop dehorning and thermocautery without local anesthesia.

ResultsPlasma meloxicam concentrations were detectable for 50 h post-administration and fit a 2-compartment model with a rapid distribution phase mean T½α = 0.22 ± 0.087 h and a slower elimination phase mean T½β = 21.86 ± 3.03 h. Dehorning caused a significant increase in serum cortisol concentrations and HR P ConclusionsTo our knowledge, this is the first published report examining the effects of meloxicam without local anesthesia on SP, activity and performance of calves post-dehorning. These findings suggest that administration of meloxicam alone immediately prior to dehorning does not mitigate signs of acute distress but may have long term physiological, behavior and performance effects.